wpf中ConverterParameter的使用

public class MultiplyConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            if (value == null)
                return 0;

            if (parameter == null)
                parameter = 1;

            double number;
            double coefficient;

            if (double.TryParse(value.ToString(), out number) && double.TryParse(parameter.ToString(), out coefficient))
            {
                return number * coefficient;//将传进来的value和parameter，传进来，然后转换为double类型
            }

            return 0;
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotSupportedException();
        }

    }